The present invention relates generally to fluid couplings, particularly for coupling a fluid line from a piece of construction equipment, to an implement.
Couplings for connecting fluid lines are well known and include a coupler socket (female half) and a nipple (male half). In some types of couplings, when the male half is inserted into the female half, a valve assembly in the female half opens to provide a flow path through the coupling. At the same time, a catch or coupling mechanism automatically engages the male half to retain the male half within the female half. Typically, the coupling mechanism can be manually released to disconnect the male half from the female half, at which point the valve assembly closes the flow path through the coupling. Such a coupling is conventionally referred to as a xe2x80x9cpush-to-connectxe2x80x9d coupling.
The male half of a coupling typically includes a tubular plug circumscribing a central passage, and a threaded fitting portion at its rear end which enables the male half to be connected to a pipe or tube. A valve assembly may also be provided in the male half. The male half narrows down at its forward end and includes an outwardly-facing circumferential groove or channel. When the male half is inserted into the female half, the coupling mechanism on the female half engages the groove on the male half to retain the male half within the female half.
One particularly useful type of push-to-connect coupling is referred to as a xe2x80x9cflush facexe2x80x9d coupling. In a flush face coupling, the front of the male half has a complimentary surface with the front of the female half such that certain engaging surfaces of the male and female half are all flush with one another. This flush face assembly is intended to prevent leakage during disconnect, and generally to prevent contaminants entering the coupling during connect and disconnect.
A number of different types of coupler sockets have been developed for receiving a male half. One known type of socket includes a cylindrical body with an internal poppet valve. The poppet valve is spring-biased into a normally closed position when the coupling is disconnected. Internal pressure in the female coupling also urges the poppet valve against its seat to prevent fluid leakage when disconnected. The body of the female half has a series of tapered openings in a circumferential arrangement near the forward end, and a series of locking balls are received in the openings. A spring-biased locking collar is slidably disposed around the coupler body, and when the male valving is inserted into the socket, the locking collar forces the locking balls radially inward into the groove in the male half to lock the male half to the female half. At the same time, the poppet valve in the female half engages with a valve assembly in the male half to open the flow passage through the coupling.
To uncouple the male half from the female half, the locking collar is moved rearwardly, which allows the locking balls to move outwardly from engagement with the groove in the male half, and thereby allow the male half to be removed from the female half. As the male half is removed, the poppet valve in the female half and the valve assembly in the male half are moved to closed positions to prevent fluid flow through the respective halves of the coupling.
Most flush face couplings are designed to connect and disconnect without pressure in the hoses and coupling. In many applications, such as in construction equipment (e.g., loaders), this is not a concern, as the female coupling half is typically connected by hose to an implement. The implement does not have a source of pressure, and so the hose and female coupling half are typically at zero pressure when the implement is disconnected. However, under some operating conditions, such as during the heat of the day, the pressure within the disconnected female coupling half can increase. If the pressure increases to a great enough extent, it can be difficult (or virtually physically impossible) to connect the male half, as the coupling components in the female half resist movement against the pressure.
It is believed some have attempted to solve this problem by using a plurality of concentric, inter-nesting valves, such that pressure upstream in the female coupling half does not prevent the connection with the male half. One such example is shown in U.S. Pat. No. 6,095,190, which includes a spring-biased ball valve (vent valve) which is concentrically located within a poppet valve (main valve). The ball valve is initially opened by an actuator engaged by a sleeve valve for pressure relief prior to the poppet valve being moved from its seat for full flow. While this two-step process may be appropriate for certain applications, it requires complex and numerous valve components, and complicated and time-consuming assembly steps, which increases the costs associated with the valve. It is further believed this design does not take into account (i.e., compensate for) pressure build-up downstream of the poppet valve, for example due to leakage past the ball valve and/or poppet valve, while the female coupling is disconnected.
It is therefore believed there is a demand for a further improved push-to-connect, flush-face coupling which overcomes at least some of the above-described drawbacks.
The present invention provides a new and unique push-to-connect, flush-face coupling, particularly for construction equipment, where the female coupling half has a valve assembly including a primary valve in the downstream portion of the coupling half, and a pressure-balanced secondary valve in the upstream portion of the coupling half. The secondary valve maintains low (preferably zero) pressure in the downstream end to allow easy connect of the male coupling half, even when there is pressure upstream of the secondary valve. The secondary valve of the valve assembly is of relatively simple construction, which facilitates manufacturing and assembly of the coupling, and thereby reduces the costs associated with the coupling. The primary valve also allows pressure to escape from the downstream end, should there be leakage past the secondary valve after the female coupling half is disconnected.
According to the present invention, the secondary valve includes a spring-biased valve sleeve received within a seal gland. The valve sleeve is axially moveable to open a flow path between the gland and the coupling body. The forward end of the valve sleeve normally seals against a seal in the coupling body when the female half is disconnected, and a second seal is retained by the gland and held against the side of the valve sleeve. Fluid pressure upstream of the secondary valve is applied along the length of the valve sleeve (preferably essentially perpendicular to the valve), which balances the valve sleeve and makes it easy to move the secondary valve during the coupling process.
The primary valve in the female coupling half includes an axially-moveable and spring-biased cylindrical face sleeve with an annular flat front face which engages flush against the annular flat front face of the male half, a cylindrical retainer sleeve received within the face sleeve and fixed to the fitting; an axially movable and spring-biased cylindrical sealing sleeve received within the retainer sleeve; and a cylindrical valve body located centrally within the sealing sleeve and also fixed to the fitting. A tubular actuator is also slidably received within the retainer sleeve, and is in engagement with the secondary valve. The actuator can be formed integral with the secondary valve or integral with the sealing sleeve; or can be a separate component.
A locking mechanism is provided with the female coupling half which cooperates with the male half to couple the male half to the female half. When coupled, the primary and secondary valves open a flow path through female half. Preferably, the locking mechanism includes openings for locking balls in the body of the cylindrical fitting, and a spring-biased locking collar which retains the locking balls in engagement with a groove in the male half when the male half is inserted into the female half, and which can be axially moved to release the locking balls and thereby allow the male half to be removed from the female half.
When the male coupling half is inserted into the female half, the valve assembly (if present) in the male half opens, and the male half urges the face sleeve of the female half rearwardly within the coupling body. The face sleeve cooperates with the sealing sleeve to also move the sealing sleeve rearwardly within the coupling body and out of sealing engagement with the valve body. When the male half is further inserted, the sealing sleeve engages the actuator, which opens the secondary valve, to thereby open up a flow path through the coupling. Since the secondary valve is pressure balanced, the secondary valve opens easily and without resistance, even when there is pressure in the female half At the same time, the locking mechanism engages the male half to couple the male half to the female half.
When the male half is to be removed, the sealing sleeve of the primary valve seals back against the valve body, and the secondary valve likewise closes to prevent fluid flow through the female half of the coupling. The valve assembly in the male half likewise returns to a closed position. The flush engagement of the male valving with the face sleeve prevents leakage of fluid during disconnect.
A seal at the forward end of the valve body in the female coupling half normally provides a seal against the sealing sleeve to prevent leakage of fluid from the female half during connect and disconnect. However, if fluid leaks around the secondary valve, for example, due to leakage past the seals of the secondary valve after the male half is disconnected from the female half, and the pressure builds up (due to this or other reasons) to an unacceptable level at the forward end of the female coupling half, the seal of the valve body has a configuration which allows the fluid to escape to atmosphere.
In a further aspect of the invention, an annular flange can be provided integral with the valve sleeve of the secondary valve. The flange fits closely within the coupling body and creates an orifice that restricts flow through the secondary valve until the male coupling half is fully connected. The flange (or other appropriate geometry) prevents sudden surges of fluid through the secondary valve during connection. When the male half is fully connected, the flange moves out of close relation with the coupling body to maximize flow and minimize the pressure drop across the secondary valve.
Thus, as described above, the present invention provides a push-to-connect coupling, particularly for construction equipment, which overcomes many of the drawbacks of previous couplings, and namely, which allows easy connect of the male coupling half, even when the female half is under pressure; and which allows pressure to escape from the downstream end of the female half, should there be leakage through the secondary valve.
Further features of the present invention will become apparent to those skilled in the art upon reviewing the following specification and attached drawings.